yucca plant cuttings
Is applying a wound dressing to yucca cuttings necessary. I have seen some yuccas where the top has been removed and they had a painted or dipped the top of the plant in melted rubber or something.
This is called wound dressing, and there's really no need for it. Plants form natural calluses over wounds, and coating them in rubber or tar just prevents that process. This article is about trees, but the principle still holds if you want to read more about it:
Yuccas are tough and used to pruning. As long as your plant gets lots of light while it's recovering, it should be fine on its own. You can read more about yucca pruning here: